Serviceability considerations of high performance steel bridges

Applications of high performance materials in structures results in smaller cross sections and much more economical designs. Smaller cross section also leads to more flexible bridges that may not satisfy the existing serviceability deflection criteria. Deflection limits were employed to avoid "undesirable structural and psychological effects due to their deformations." Results of prior studies indicate that deflection and L/D limits do not necessarily address these objectives. Existing limits do not prevent damages in structures because they check global deflection while the damages are mostly the consequence of local deformations. Furthermore, human comfort can be achieved directly by limiting the more relevant vibration characteristics such as acceleration. Thus, there is a need for additional work on understanding bridge vibrational characteristics and to provide simple methods to estimate bridge dynamic response parameters that can be use in design, which are the objectives of this study and some of the results are presented in this paper.